engleski

Stability and universality of few-body systems

Ground state properties of weakly bound few- body systems consisting of helium and spin- polarized hydrogen isotopes, and alkali atoms have been explored. Stability of different cluster species has been tested with a special emphasis on a universality of quantum halo states - weakly bound systems with a radius extending well into the classically forbidden region. The study of realistic systems is supplemented by model calculations in order to analyze how low-energy properties depend on the interaction potential. The use of variational and diffusion Monte Carlo methods enabled very precise calculation of both size and binding energy of few-body systems. Using dimensionless measures of the binding energy and cluster size, studied atomic clusters are compared to other known halos in different fields of physics. Different characteristic scaling lengths, which make size-energy ratio to be universal, are tested. As the scaled binding energy decreases, samba and tango type trimers separate from Borromean type. Research is extended to tetramers and pentamers. Furthermore, the structural properties of different trimers are compared with the most recent experimental results obtained by Coulomb explosion imaging of diffracted clusters.

few-body universality ; quantum halo ; quantum Monte Carlo

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